Most application systems include menu systems for the user's convenience and effective manipulations. However, in the case of complicated systems providing many functions, it is difficult to construct menu systems having effective item classifications and access methods. For example, menu systems of conventional two-dimensional desk top application systems are constructed to provide menu browsing and selection functions using interfaces such as keyboards and mice. However, such menu browsing and selection functions are not suitable for three-dimensional systems due to, for example, spatial limitation.
Various studies have been conducted on three-dimensional menu systems to provide effective methods of manipulating systems in three-dimensional space. TULIP [D. A. Bowman, C. A. Wingrave, “Design and evaluation of menu systems for immersive virtual environments,” IEEE virtual reality, Yokohama, Japan, 2001, p. 149-156.] provides a method of selecting a menu from a list of maximum sixteen menus in virtual environments by using a combination of fingers and thumbs wearing pinch gloves. Although the method is eidetic owing to interaction using fingers and thumbs, it is difficult to commercialize the method for end users because of expensive equipment. Butz [A. Butz, M. Gross, A. Kruger, “Tuister: a tangible UI for hierarchical structures”, Proceedings of the ninth international conference on Intelligent User Interface, New York, USA, 2004, p. 223-225.] has introduced a hierarchical three-dimensional menu system “TUISTER” using an interface based on six OLED displays. The hierarchical three-dimensional menu system is advantageous in that menus can be eidetically manipulated through a rotational input tool such as a mouse wheel but is disadvantageous in terms of a limited number of displays and a one-dimensional input method. Poupyrev [I. Poupyrev, D. S. Tan, M. Billinghurst, H. Kato, H. Regenbrecht, N. Tetsutani, “Developing a generic augmented-reality interface”, IEEE Computer, 2002, 35(3), p. 44-50] has proposed an augmented-reality menu system based on a marker supporting sensible interaction. However, since one marker corresponds to one function, it is difficult to apply the proposed system to complicated systems.